Thanks in part to the inherent awesomeness of the word itself, it seems everyone is talking about ultracapacitors. Ultracapacitors store energy in an electrical field between two plates. They can charge faster than batteries, emit powerful pulses of electricity, and last almost indefinitely. Several companies make them, but the most hyped by far is EEStor. EEStor's ultracapacitors are set to power the ZENN City Car, an electric car with a 250-mile range that's supposed to arrive next year.
The only problem: No one has ever seen a prototype from EEStor. The secretive company's latest milestone, according to a press release, was "certification of the completeness of the powder crystallization .... [which] provides the path for the possibility of EEStor, Inc. providing the published energy storage for present products and major advancements in energy storage for future products."
Provides the path for the possibility? Not the most confidence-inspiring announcement.
Ultracapacitors store much less energy than batteries, so until EEStor or someone else arrives with a game-changer, ultracapacitors are more likely to assist batteries than replace them. Ultracapacitors could handle quick bursts of power while the battery supplies the driving range. The pairing could work beautifully. But it would be expensive, and lithium ion isn't going away anytime soon.
The concept of using a capacitor for a surge has been around some time. One must also consider size, cost and weight. One still needs an energy source to charge the capacitor and maintain the charge. This concept just reduces some loss from the battery during the surge request for energy and thus could increase the miles of a vehicle. An energy annalysis is needed.
The upper limit of energy storage by batteries is set by the laws of chemistry and we've pretty much maxed that out. In order to provide a real energy storage breakthrough super capacitors need to store significantly more energy than current batteries.
What is probably the most important difference between batteries and supercapacitors is their energy curve, or lack of it: batteries maintain a relatively stable voltage until they are nearly exhausted. In the case of a lithium-ion cell, for instance, it is a bit over 3 volts for most of its charge cycle, and then drops rapidly to nearly nothing. so the motor feeds off a steady, nearly unvarying power supply.
All capacitors (and supercapacitors) start out at, say, 100 volts when fully charged and their voltage drops on a nearly straight slope as they are depleted.
This makes it much more complicated to use supercaps rather than batteries to power an EV, but this may be overcome. Early cell phones were so big, heavy, clumsy and expensive that they were originally called "car phones" and were mounted directly in vehicles (the one in my BMW weighed approximately 40 lbs. and its electronics filled a box that took up about 200 square inches of space); the relentless miniaturization of components helped to shrink their size, weight, cost and energy usage to the tiny ubiquitous units we have today.
It is unlikely that supercap controllers will be able to shrink quite so dramatically since they will have to deal with much higher voltages than cell phones do, but they just might drop in size and cost enough to give a significant edge over batteries in EV applications.
If we can switch to supercaps to power EVs, there will be several benefits: they will be able to be charged very rapidly-- with advanced high-speed chargers, perhaps 5 minutes or so, or faster than we refuel gasoline cars today; they are likely to last significantly longer than the cars themselves; and since supercaps do not need lithium, which is in short supply, we can avoid a national crisis due to availability bottlenecks.
Supercaps can be made of phosphates and other inexpensive nontoxic materials.
Capacitors, in the past has been nothing more than a DC power storage. Unless power is provided to the capacitors they will eventually run "dry" and will require a charge.
If the supercapacitors, has a self charging componet, it to will require charging from time to time.
Like most storage devices, capacitors have a cap to the amount of power one can store.
It will be interesting to see how these supercapacitors can mantain its power flow without a chrage of its own.
Great comments. Caps and Battery combos are the only power source that really works in practice from what we have seen in the labs - caps help the BMS protect the batteries from high current short duration demands.
The application of EEStor and or it's competitors to real car applications is the only thing that matters. Check out the new Plug-in Electric Car Guide and it's upcoming update editions to see who is real using this technology. Guide can be found at http://electric-cars-today.com
You say, "Capacitors, in the past has been nothing more than a DC power storage. Unless power is provided to the capacitors they will eventually run "dry" and will require a charge." ??? Capacitors have always been DC storage devices, and always will be... they don't store AC, water, compressed air or anything else. With the exception of the mPhase battery that is still in the labs, all batteries and caps require periodic charging.
You say "Like most storage devices, capacitors have a cap to the amount of power one can store." Do you think there are storage devices that do NOT have a storage limit? A coffee cup holds no more than a cup of coffee... batteries and capacitors have limits as well, no exceptions. To say otherwise would mean that you think there are batteries that have unlimited capacity or indefinite limits. That is not the case.
"If the supercapacitors, has a self charging componet , it to will require charging from time to time." Do you think there are any batteries or other storage systems that do NOT require charging, regardless of whether they have or do not have "self charging componets"? A battery is like a bank account: if you don't make any deposits, there is no money to withdraw.
"It will be interesting to see how these supercapacitors can mantain its power flow without a chrage of its own." Aside from the typographical and grammatical errors, that statement is unintelligible. Before you clutter up the discussion, please make sure your comment actually makes some sense, is accurate, and actually contributes something.
SET4QWC: thanks for the link-- that's a good resource. But not all batteries need help from capacitors-- the Altair NanoSafe battery can be charged and discharged so rapidly that capacitors don't add any functionality; the NanoSafe drawbacks are a somewhat reduced energy density and their high price currently, and supercapacitors would do nothing to help that. And EEStor's performance claims have not been verified, but if they ever are, they say their supercaps can give an all-electric range of 400 miles, if I recall correctly, and would be even cheaper than batteries. I hope.
If Iron Man could shrink the power thingy in the movie, I'm sure this company can...Non believers!!!
Lithium-ion batteries used in hybrid cars, laptops and cell phones have occasionally undergone recalls and false scares concerning the possibility of exploding. Stanford University scientists have created lithium-sulfide electrodes that could create batteries that last four times longer and avoid any risk of possible explosions, Technology Review reports.